Sway limiting device on a sedimentation unit



T. S. WOOH SWAY LIMITING DEVICE ON A SEDIMENTATION UNIT Filed 001;. 7, 1957 I I Nov. 25, 1958 2 Sheets-Sheet 1 INVENTOR. T/zamas 6'. Noah 8W0- J h LLK Nov. 25, 1958 T. s. WOOH SWAY LIMITING DEVICE ON A SEDIMENTATION UNIT Filed Oct. 7, 1957 2 Sheets-Sheet 2 INVEN TOR. 7710/7786 6? Woo/7 United States Patent SWAY LllVIITING DEVICEON A'SEDIMENTATION UNIT Thomas'S. Wooh, Wilton, Conn., assignor to Dorr-Oliver Incorporated, Stamford, Conn., a corporation of Delaware Application October 7, 1957, Serial No. 688,600

2 Claims. ((11. 210-531) This invention relates to sedimentation units and particularly to raking apparatus employable in such units to effect removal of settled solids therefrom.

' A very general object of the invention is the provision of improved means for limiting non-axial movement between elongated concentric members in structures in which one of such elongated members carries radially extending arms and is axially movable while the other elongated member is axially fixed but rotatable and serves as a driving means for the radial arms by means of rods or other connecting members. In accordance with the invention the movement-limiting means are adapted to automatically engage and disengage from operative position upon relative axial movement of the elongated members.

A specific object of the invention is to provide an inexpensive, easily mounted, yet efficient device for useon sedimentation units to prevent side sway or non-axial movement of the centrally disposed axially movable or liftable shaft upon which radially extending rake carrying arms are mounted for rotation.

In the usual construction of sedimentation units, a typical example of which is shown in U. S. Patent No. 2,650,707 issued to Scott on September 1, 1953, radially extending rake carrying arms are mounted on the lower portion of a liftable and rotatable central shaft and are caused to rotate by means of a so-called torque tube positioned concentrically around the upper portion of the liftable shaft. The torque tube is itself rotated by conventional driving means and transmits rotation to the first shaft and rake arms by means of drive rods connecting the torque tube and rake arms.

During operation, such structures are subjected to varying loads which in turn effect a radial or non-axial displacement (sway) of the liftable shaft thus throwing it out of true concentricity with the torque tube. It is to the correction of this particular problem that the present invention is directed.

In order that the invention may be more readily understood and carried into effect, reference is made to the accompanying drawings and description thereof which show by way of example a preferred embodiment of the invention.

In the drawings:

Fig. 1 is a side sectional view of a sedimentation unit embodying the invention, certain elements being shown in elevation for purposes of clarity.

Fig. 2 is an enlarged partial view of the structure shown in Fig. 1 showing in greater detail the juxtaposition of the elements of the present invention, dotted lines being used to illustrate relative movement of such elements upon lifting of the rake carrying arms by the central shaft.

Fig. 3 is an elevational plan view taken in the plane of lines 33 of Fig. 2, certain elements being omitted for purposes of clarity.

Fig. 4 is a view taken in the plane of lines 4-4 of III 2,861,693 Patented Nov. I 25, 19 5 8 ice Fig. 3, dotted lines being added to illustrate movement of elements.

Fig. 5 is a view taken in the plane of lines 5-5 of Fig. 3.

The sedimentation unit illustrated in the drawingscomprises the known structure including a tank 10 having an overflow launder 11, sludge outlet 12, and a suitable feedwell 13. Mounted at the top of the tank is a superstructure 14 .which provides support for the driving mechanism and also enables access by conventional walkways. A suitable drive unit 16 is mounted on the superstructure as is a lifting device 17 which is employed to lift the raking mechanism upwardly.

The lifting device 17 is attached to a central shaft 18 to the lower end portion of which is attached a pair of oppositely extending rake carrying arms 19. To the bottom of such arms there are attached conventional rake blades 21. A so-called torque tube 22 'is provided which is axially aligned and concentrically positioned about an upper portion-of the liftable shaft 18. In operation, the torque tube is rotatable, but is substantially fixed against axial movement. Rotation of such tubeis effected in suitable manner by the drive unit 16 and transmits rotation to the rake carrying arms 19 by means of drive rods 23 which extend radially from the torque tube to engage the rake arms 19. In this arrangement, lifting of the central shaft causes any given point on 'drive rods 23 to describe an arcuate path, which, as hereinafter described in greater detail, is in such a direction as to effect disengagement of the sway limiting device to render it inoperative.

It will be noted that the torque tube is not liftable, but remains in an axially fixed position. It is also to be noted that the torque tube is spaced above the rake arms in order to provide space for lifting of such arms. In order to accommodate changes in the relative positions of the rake arms and the drive rods upon lifting of such arms, drive rods23 engage brackets 24 in such a manner that they and the rake arms are radially slideable relative to each other. Y

Thus, as the rake arms rise vertically, the outer ends of rods 23 move upward in an arcuate path which causes a resultant outward movement of the rod ends, such movement being accommodated by the brackets 24 which the rod ends engage loosely.

As previously mentioned, certain conditions of unbalance cause unequal non-axial or radial forces to be applied to the liftable shaft 18 thus causing it to move out of true concentricity with torque tube 18.

In order to provide a positive limit or block against such non-axial movement there is provided, in accordance with this invention, the combination of a stabilizer bracket 26 mounted on the upper chord or stringer 27 of rake carrying arms 19 and a complementary stabilizer guide 28 mounted on the drive rods 23 intermediate the ends thereof, preferably on a cross member 29 as best shown in Figs. 3 and 5.

It will be noted that each of the stabilizing elements (26 and 28) has a contact surface, 26' and 28', facing radially with respect to the central shaft. These surfaces face in opposite directions and are adapted to be brought into face to face contact with each other.

The stabilizer guide surface engages the stabilizer bracket surface snugly when the rakes are in the down position thus preventing any radial motion of either the rake carrying arms or the liftable shaft 18 relative to torque tube 22.

When the rake carrying arms are lifted, the contact surface 28' of stabilizer guide 28 on each drive rod moves in an arcuate path away from the contact surface 26 of stabilizer bracket 26 thus automatically disengaging the elements.

It is important that the stabilizer bracket 26 and guide 28 are mounted to move away from each other upon raising of the rake structure. In the preferred embodiment, this is accomplished by an arrangement of parts in which the drive members angle radially downwardly to engage the brackets 24 so that when the rake structure is lifted, each drive rod 23 which is pivoted on the torque tube as at 31 to enable movement in a generally vertical plane, swings its outer end upwardly thus causing the stabilizer guide 28 to describe an are moving slightly outwardly with respect to the stabilizer bracket 26.

For ease of operation, it is desirable that the stabilizer guide have a curved surface which insures smoother initial egagement with the bracket.

Although the embodiment shown comprises only a single-plane engaging or contacting surface on both the bracket and guide, this invention extends also to arrangements wherein either member is made in the form of a track to accept the other member, thus providing additional support against relative movement of the members during operation.

Installation of the device of this invention is simplicity itself, it being only necessary to mount the stabilizer guide on the drive rod, then, with the rake carrying arms in the lowered position, move the stabilizer bracket snugly against the surface of the guide and Weld or otherwise secure the bracket in place on the rake carrying arm. It will be noted that in the modification illustrated, in which the bracket is vertical and the drive rod angles downwardly, the bracket is secured in place on the inside of the guide. That is to say, with respect to the torque tube and liftable shaft, the stabilizer bracket is closer to the shaft than is the stabilizer guide. This is important in the construction shown because only by this arrangement is it possible for the stabilizer guide to disengage from the bracket upon lifting of the rakes.

In certain structures, when the unit is in the down position, the drive rods may be horizontal. This would occur, for instance, where steeply sloped tank bottoms are used. In such a structure the arcuate path of the drove rods is toward the central shaft when the unit is lifted. Hence, the stabilizer guide should be placed inside the bracket. Also, if the bracket on the arms has an inwardly and downwardly sloped contacting face, then the arcuate path of the drive rod and guide, even though initially away from the central shaft, will disengage from the guide. In short then, the invention may be said to encompass broadly the concept of engaging and disengaging the guide and bracket elements by arcuate movement of that element mounted on the drive rod.

Advantages of the invention are numerous and include, inter alia, simplicity of installation, positive operation and the need for only a small amount of space.

Since the new device requires so little space, the invention offers an additional advantage of enabling the use of larger and stronger rake carrying arms and/or the use of stilts for mounting the rake blades without deepening of the tank itself to accommodate such larger equipment.

I claim:

1. In a sedimentation unit of the type including a central shaft axially movable from a down to an up position, a plurality of radially extending rake carrying arms secured to said shaft, a rotatable torque tube concentrically mounted about an upper portion of said central shaft and spaced above said rake carrying arms, and drive rods connecting said torque tube to each of said rake carrying arms enabling driving of said arms by said torque tube, each of said drive rods extending in a radial direction from said tube to said arms and being pivotally mounted at one end and slidably mounted at the opposite end whereby upon lifting of said central shaft and arms any point on said drive rods travels in an arcuate path; the improvement which comprises means limiting nonaxial movement of said central shaft relative to said concentrically mounted rotatable torque tube, said means comprising a first element mounted on each of said drive rods intermediate the torque tube and said arms, a complementary second element mounted on each of said arms, and said first and second elements being positioned in contact with each other with the central shaft in the down position and disengageable from such contact upon lifting of said central shaft to effect arcuate movement of said first elements on said drive rods.

2. A structure for limiting relative non-axial movement between two elongated concentric members a first one of which carries radially extending arms rotatable about the longitudinal axis of said concentric members,

comprising an elongated connecting member extending between each of said arms and the second of said concentric members, a first element fixed on each of said connecting members intermediate its points of connection with said arm and said second concentric member, a second element fixedly mounted on each of said arms, one of said first and second elements having a contact surface facing radially inwardly and the other of said elements having a contact surface facing radially outwardly, and said first and second elements being fixedly mounted on said rod and said arm with said radially facing surfaces in contact with each other.

References Cited in the file of this patent UNITED STATES PATENTS 

